Reflections on a Copenhagen-Minneapolis Axis in Bioorganic Chemistry.

The international peptide community rejoiced when one of its most distinguished members, Morten Meldal of Denmark, shared the 2022 Nobel Prize in Chemistry. In fact, the regiospecific solid-phase "copper(I)-catalyzed 1,3-dipolar cycloaddition of terminal alkynes to azides" (CuACC) reaction-that formed the specific basis for Meldal's recognition-was reported first at the 17th American Peptide Symposium held in San Diego in June 2001. The present perspective outlines intertwining conceptual and experimental threads pursued concurrently in Copenhagen and Minneapolis, sometimes by the same individuals, that provided context for Meldal's breakthrough discovery. Major topics covered include orthogonality in chemistry; the dithiasuccinoyl (Dts) protecting group for amino groups in α-amino acids, carbohydrates, and monomers for peptide nucleic acids (PNA); and poly(ethylene glycol) (PEG)-based solid supports such as PEG-PS, PEGA, and CLEAR [and variations inspired by them] for solid-phase peptide synthesis (SPPS), solid-phase organic synthesis (SPOS), and combinatorial chemistry that can support biological assays in aqueous media.

Physiological response in E. coli to YdgR overexpression depends on whether the protein has an intact function.

Membrane transport proteins are essential for the transport of a wide variety of molecules across the cell membrane to maintain cellular homeostasis. Generally, these transport proteins can be overexpressed in a suitable host (bacteria, yeast, or mammalian cells), and it is well documented that overexpression of membrane proteins alters the global metabolomic and proteomic profiles of the host cells. In the present study, we investigated the physiological consequences of overexpression of a membrane transport protein YdgR that belongs to the POT/PTR family from E. coli by using the lab strain BL21 (DE3)pLysS in its functional and attenuated mutant YdgR-E33Q. We found significant differences between the omics (metabolomics and proteomics) profiles of the cells expressing functional YdgR as compared to cells expressing attenuated YdgR, e.g., upregulation of several uncharacterized y-proteins and enzymes involved in the metabolism of peptides and amino acids. Furthermore, molecular network analysis suggested a relatively higher presence of proline-containing tripeptides in cells expressing functional YdgR. We envisage that an in-depth investigation of physiological alterations due to protein over-expression may be used for the deorphanization of the y-gene transportome.

The Y-ome Conundrum: Insights into Uncharacterized Genes and Approaches for Functional Annotation.

The ever-increasing availability of genome sequencing data has revealed a substantial number of uncharacterized genes without known functions across various organisms. The first comprehensive genome sequencing of E. coli K12 revealed that more than 50% of its open reading frames corresponded to transcripts with no known functions. The group of protein-coding genes without a functional description and/or a recognized pathway, beginning with the letter "Y", is classified as the "y-ome". Several efforts have been made to elucidate the functions of these genes and to recognize their role in biological processes. This review provides a brief update on various strategies employed when studying the y-ome, such as high-throughput experimental approaches, comparative omics, metabolic engineering, gene expression analysis, and data integration techniques. Additionally, we highlight recent advancements in functional annotation methods, including the use of machine learning, network analysis, and functional genomics approaches. Novel approaches are required to produce more precise functional annotations across the genome to reduce the number of genes with unknown functions.

Drug-Eluting Bead, Irinotecan Therapy of Unresectable Intrahepatic Cholangiocarcinoma (DELTIC) with Concomitant Systemic Gemcitabine and Cisplatin.

BACKGROUND: Unresectable intrahepatic cholangiocarcinoma (ICC) carries a poor prognosis, and currently there are moderately established chemotherapeutic [gemcitabine/cisplatin (Gem/Cis)] treatments to prolong survival. The purpose of this study was to assess the efficacy of irinotecan drug-eluting beads (DEBIRI) therapy by transarterial infusion in combination with systemic therapy in unresectable ICC. PATIENTS AND METHODS: This is a prospective, multicenter, open-label, randomized phase II study (Clin Trials: NCT01648023-DELTIC trial) of patients with ICC randomly assigned to Gem/Cis with DEBIRI or Gem/Cis alone. The primary endpoint was response rate. RESULTS: The intention-to-treat population comprised 48 patients: 24 treated with Gem/Cis and DEBIRI and 22 with Gem/Cis alone (2 screen failures). The two groups were similar with respect to the extent of liver involvement (35% versus 38%) and presence of extrahepatic disease (29% versus 14%, p = 0.12). Median numbers of chemotherapy cycles were similar (6 versus 6), as were rates of grade 3/4 adverse events (34% for the Gem/Cis-DEBIRI group versus 36% for the Gem/Cis group). The overall response rate was significantly greater in the Gem/Cis-DEBIRI arm versus the Gem/Cis arm at 2 (p < 0.04), 4 (p < 0.03), and 6 months (p < 0.05). There was significantly more downsizing to resection/ablation in the Gem/Cis-DEBIRI arm versus the Gem/Cis arm (25% versus 8%, p < 005), and there was improved median progression-free survival [31.9 (95% CI 8.5-75.3) months versus 10.1 (95% CI 5.3-13.5) months, p = 0.028] and improved overall survival [33.7 (95% CI 13.5-54.5) months versus 12.6 (95% CI 8.7-33.4) months, p = 0.048]. CONCLUSION: Combination Gem/Cis with DEBIRI is safe, and leads to significant improvement in downsizing to resection, improved progression-free survival, and overall survival.

Which countries need COVID-19 vaccines the most? Development of a prioritisation tool.

BACKGROUND: The COVID-19 pandemic and associated non-pharmaceutical interventions (NPIs) have affected all countries. With a scarcity of COVID-19 vaccines there has been a need to prioritize populations, but assessing relative needs has been challenging. The COVAX Facility allocates vaccines to cover 20% of each national population, followed by a needs assessment that considers five quantitative metrics alongside a qualitative assessment. The objective of this study was to identify the most important factors for assessing countries' needs for vaccines, and to weight each, generating a scoring tool for prioritising countries. METHODS: The study was conducted between March and November 2021. The first stage involved an online Delphi survey with a purposive and snowball sample of public health experts, to reach consensus on country-level factors for assessing relative needs for COVID-19 vaccines. The second stage involved a discrete choice experiment (DCE) to determine weights for the most important factors. RESULTS: Responses were received from 28 experts working across 13 different countries and globally. The most common job titles reported were director and professor, with most based in national public health institutes (n = 9) and universities (n = 8). The Delphi survey found 37 distinct factors related to needs. Nine of the most important factors were included in the DCE. Among these, the most important factor was the 'proportion of overall population not fully vaccinated' (with a mean weight of 19.5), followed by 'proportion of high-risk population not fully vaccinated' (16.1), 'health system capacity' (14.2), 'capacity to purchase vaccines' (11.9) and the 'proportion of the population clinically vulnerable' (11.3). CONCLUSIONS: Several factors exist, extending beyond those currently used, which may lead to some countries having a greater need for vaccines compared to others. By assessing relative needs, this scoring tool can build on existing methods to further the role of equity in global COVID-19 vaccine allocation.

Peptide Antibody Reactivity to Homologous Regions in Glutamate Decarboxylase Isoforms and Coxsackievirus B4 P2C.

Two isoforms of the glutamate decarboxylase (GAD) enzyme exist, GAD65 and GAD67, which are associated with type 1 diabetes (T1D) and stiff-person syndrome (SPS), respectively. Interestingly, it has been reported that T1D patients seldom develop SPS, whereas patients with SPS occasionally develop T1D. In addition, coxsackievirus B4 (CVB4) has previously been proposed to be involved in the onset of T1D through molecular mimicry. On this basis, we aimed to examine antibody cross-reactivity between a specific region of GAD65 and GAD67, which has high sequence homology to the nonstructural P2C protein of CVB4 to determine potential correlations at antibody level. Monoclonal peptide antibodies generated in mice specific for a region with high similarity in all three proteins were screened for reactivity along with human sera in immunoassays. In total, six antibodies were generated. Two of the antibodies reacted to both GAD isoforms. However, none of the antibodies were cross-reactive to CVB, suggesting that antibody cross-reactivity between GAD65 and CVB, and GAD67 and CVB may not contribute to the onset of T1D and SPS, respectively.

Production and Characterization of Peptide Antibodies to the C-Terminal of Frameshifted Calreticulin Associated with Myeloproliferative Diseases.

Myeloproliferative Neoplasms (MPNs) constitute a group of rare blood cancers that are characterized by mutations in bone marrow stem cells leading to the overproduction of erythrocytes, leukocytes, and thrombocytes. Mutations in calreticulin (CRT) genes may initiate MPNs, causing a novel variable polybasic stretch terminating in a common C-terminal sequence in the frameshifted CRT (CRTfs) proteins. Peptide antibodies to the mutated C-terminal are important reagents for research in the molecular mechanisms of MPNs and for the development of new diagnostic assays and therapies. In this study, eight peptide antibodies targeting the C-terminal of CRTfs were produced and characterised by modified enzyme-linked immunosorbent assays using resin-bound peptides. The antibodies reacted to two epitopes: CREACLQGWTE for SSI-HYB 385-01, 385-02, 385-03, 385-04, 385-07, 385-08, and 385-09 and CLQGWT for SSI-HYB 385-06. For the majority of antibodies, the residues Cys1, Trp9, and Glu11 were essential for reactivity. SSI-HYB 385-06, with the highest affinity, recognised recombinant CRTfs produced in yeast and the MARIMO cell line expressing CRTfs when examined in Western immunoblotting. Moreover, SSI-HYB 385-06 occasionally reacted to CRTfs from MPN patients when analysed by flow cytometry. The characterized antibodies may be used to understand the role of CRTfs in the pathogenesis of MPNs and to design and develop new diagnostic assays and therapeutic targets.

Perfluoro-tert-butanol for selective on-resin detritylation: a mild alternative to traditionally used methods.

Solid-phase synthesis of cyclic, branched or side-chain-modified peptides typically involves introduction of a residue carrying a temporary side-chain protecting group that undergoes selective on-resin removal. In particular, Nα-Fmoc-Nε-(4-methyltriphenylmethyl) (Mtt)-protected lysine and its shorter analogues are commercially available and extensively used in this context. Nevertheless, rapid reliable methods for on-resin removal of Mtt groups in the presence of tert-butyloxycarbonyl (Boc) groups are needed. Current commonly used conditions involve low concentrations (1-3%) of trifluoroacetic acid (TFA) in dichloromethane, albeit adjustment to each specific application is required to avoid premature removal of Boc groups or cleavage from the linker. Hence, a head-to-head comparison of several deprotection conditions was performed. The selected acids represent a wide range of acidity from TFA to trifluoroethanol. Also, on-resin removal of the N-(4-methoxytriphenylmethyl) (Mmt) and O-trityl groups (on serine) was investigated under similar conditions. The mildest conditions identified for Mtt deprotection involve successive treatments with 30% hexafluoroisopropanol (HFIP) or 30% perfluoro-tert-butanol [(CF3)3COH] in dichloromethane (3 × 5 or 3 × 15 min, respectively), while 30% HFIP, 30% (CF3)3COH, or 10% AcOH-20% trifluoroethanol (TFE) in CH2Cl2 (3 × 5 min) as well as 5% trichloroacetic acid in CH2Cl2 (3 × 2 min) enabled Mmt removal. Treatment with 1% TFA with/without 2% triisopropylsilane added (3 × 5 min), but also prolonged treatment with 30% (CF3)3COH (5 × 15 min), led to selective deprotection of an O-Trt group on a serine residue. In all cases, the sequences also contained N-Boc or O-tBu protecting groups, which were not affected by 30% HFIP or 30% (CF3)3COH even after a prolonged reaction time of 4 h. Finally, the optimized conditions involving HFIP or (CF3)3COH proved applicable also for selective deprotection of a longer resin-bound peptide [i.e., Ac-Gly-Leu-Leu-Lys(Mtt)-Arg(Pbf)-Ile-Lys(Boc)-Ser(tBu)-Leu-Leu-RAM-PS] as well as allowed for an almost complete deprotection of a Dab(Mtt) residue.

New Zealand Population Norms for the EQ-5D-5L Constructed From the Personal Value Sets of Participants in a National Survey.

OBJECTIVES: To derive New Zealand (NZ) population norms for the EQ-5D-5L and to examine the association between participants' sociodemographic characteristics and their health-related quality of life. METHODS: Data from the 2018 NZ EQ-5D-5L valuation study (n = 2468) were used. Each participant's 5-digit profile was converted to a single utility value using their personal value set. The profiles, mean utility values, and mean EuroQol visual analog scale (EQ-VAS) scores were summarized by dimension and disaggregated by age group and gender. Multivariable logistic and Tobit regressions were used to investigate the association between participants' sociodemographic characteristics and the EQ-5D-5L dimensions, utility values, and EQ-VAS scores. RESULTS: The mean utility value was 0.847 and the mean EQ-VAS score was 74.8. Of the 3125 possible EQ-5D-5L profiles, 25 profiles represented the current health status of the majority of participants (78%). The odds of having problems with anxiety or depression was greatest for people aged 18 to 24 years and decreased with age. People with a long-term disability or chronic illness had greater odds of problems on all dimensions and lower (poorer) utility values and EQ-VAS scores. Age, ethnicity, employment status, long-term disability, and chronic illness were associated with utility. CONCLUSION: EQ-5D-5L population norms were derived for the NZ population using the personal value sets of 2468 participants. Consistent with other countries' population norms, EQ-5D-5L utility values and EQ-VAS scores were associated with age, employment status, long-term disability, and chronic illness. These norms will support resource allocation decision making and help in understanding the health-related quality of life of the NZ population.

Dual High-Resolution α-Glucosidase and PTP1B Inhibition Profiling Combined with HPLC-PDA-HRMS-SPE-NMR Analysis for the Identification of Potentially Antidiabetic Chromene Meroterpenoids from Rhododendron capitatum.

Thirteen previously undescribed chromene meroterpenoids, capitachromenic acids A-M (3-6, 7a, 7b, 8a, 8b, 9a, 9b, 10a, 10b, and 11b), were identified from an ethyl acetate extract of Rhododendron capitatum, using dual high-resolution α-glucosidase and PTP1B inhibition profiling in combination with HPLC-PDA-HRMS-SPE-NMR. In addition, one known chromene meroterpenoid, daurichromenic acid (15), and its biosynthetic precursor, grifolic acid (12), two C-methylated flavanones, (2S)-5,7,4'-trihydroxy-8-methylflavanone (1) and farrerol (2), and two triterpenoids, oleanolic acid (14a) and ursolic acid (14b), were identified. New structures were elucidated by extensive 1D and 2D NMR analysis, and absolute configurations of new chromene meroterpenoids were assigned by analysis of their ECD spectra on the basis of the empirical chromane helicity rule and from Rh2(OCOCF3)4-induced ECD spectra by applying the bulkiness rule. Compounds 5, 9a, 9b, 12, and 15 showed α-glucosidase inhibitory activity with IC50 values ranging from 8.0 to 93.5 µM, while compounds 3, 5, 8b, 9a, 9b, 10b, 11b, 12, and 15 showed PTP1B inhibitory activity with IC50 values ranging from 2.5 to 68.1 µM.

Evaluation of Indocyanine Green Fluorescence Imaging for Intraoperative Identification of Liver Malignancy.

INTRODUCTION: There is early evidence that indocyanine green (ICG) fluorescence imaging has the ability to detect metastatic and primary malignancies in the liver that are too small to be identified by other methods. However, the rate of false positives and false negatives remains unknown. MATERIALS AND METHODS: This is a single institution prospective single-arm study. Patients with suspected hepatic or pancreatic malignancies were intravenously injected with ICG one to three days prior to their scheduled surgical therapy. At the beginning of the procedure, the liver was assessed with fluorescence imaging and all identified lesions were biopsied and evaluated. RESULTS: Twenty-three patients were enrolled from April 2015 through February 2016. Fifteen patients with confirmed malignancy had adequate fluorescence imaging evaluation of the liver; 10 with pancreatic primary malignancies and five with hepatic primaries. Fluorescence imaging was the only modality that identified nine concerning hepatic lesions, all of which were benign on pathology examination. Out of 11 malignant hepatic masses, six were visible on fluorescence imaging. Out of nine benign hepatic lesions, five were visible. No side effects or complications of the fluorescence imaging were encountered. The sensitivity for ICG fluorescence was 45.5%, the specificity 21.2%, the positive predictive value 25%, and the negative predictive value 40%. CONCLUSION: Intraoperative hepatic assessment with ICG fluorescence imaging to identify malignancy in the liver is feasible and safe. However, in this study the significant number of false positives limit the utility of the technique. Our preliminary data do not support its routine use for detection of malignancies in the liver.

The Miami International Evidence-based Guidelines on Minimally Invasive Pancreas Resection.

OBJECTIVE: The aim of this study was to develop and externally validate the first evidence-based guidelines on minimally invasive pancreas resection (MIPR) before and during the International Evidence-based Guidelines on Minimally Invasive Pancreas Resection (IG-MIPR) meeting in Miami (March 2019). SUMMARY BACKGROUND DATA: MIPR has seen rapid development in the past decade. Promising outcomes have been reported by early adopters from high-volume centers. Subsequently, multicenter series as well as randomized controlled trials were reported; however, guidelines for clinical practice were lacking. METHODS: The Scottisch Intercollegiate Guidelines Network (SIGN) methodology was used, incorporating these 4 items: systematic reviews using PubMed, Embase, and Cochrane databases to answer clinical questions, whenever possible in PICO style, the GRADE approach for assessment of the quality of evidence, the Delphi method for establishing consensus on the developed recommendations, and the AGREE-II instrument for the assessment of guideline quality and external validation. The current guidelines are cosponsored by the International Hepato-Pancreato-Biliary Association, the Americas Hepato-Pancreato-Biliary Association, the Asian-Pacific Hepato-Pancreato-Biliary Association, the European-African Hepato-Pancreato-Biliary Association, the European Association for Endoscopic Surgery, Pancreas Club, the Society of American Gastrointestinal and Endoscopic Surgery, the Society for Surgery of the Alimentary Tract, and the Society of Surgical Oncology. RESULTS: After screening 16,069 titles, 694 studies were reviewed, and 291 were included. The final 28 recommendations covered 6 topics; laparoscopic and robotic distal pancreatectomy, central pancreatectomy, pancreatoduodenectomy, as well as patient selection, training, learning curve, and minimal annual center volume required to obtain optimal outcomes and patient safety. CONCLUSION: The IG-MIPR using SIGN methodology give guidance to surgeons, hospital administrators, patients, and medical societies on the use and outcome of MIPR as well as the approach to be taken regarding this challenging type of surgery.

What matters most to patients when choosing treatment for mild-moderate asthma? Results from a discrete choice experiment.

BACKGROUND: An as-needed combination preventer and reliever regimen was recently introduced as an alternative to conventional daily preventer treatment for mild asthma. In a subgroup analysis of the PRACTICAL study, a pragmatic randomised controlled trial of budesonide-formoterol reliever therapy versus maintenance budesonide plus terbutaline reliever therapy in adults with mild asthma, we recently reported that about two-thirds preferred as-needed combination preventer and reliever therapy. The aim of this study was to determine the relative importance of attributes associated with these two asthma therapies in this subgroup of participants who indicated their preferred treatment in the PRACTICAL study. METHODS: At their final study visit, a subgroup of participants indicated their preferred treatment and completed a discrete choice experiment using the Potentially All Pairwise RanKings of all possible Alternatives method and 1000minds software. Treatment attributes and their levels were selected from measurable study outcomes, and included: treatment regimen, shortness of breath, steroid dose and likelihood of asthma flare-up. RESULTS: The final analysis dataset included 288 participants, 64% of whom preferred as-needed combination preventer and reliever. Of the attributes, no shortness of breath and lowest risk of asthma flare-up were ranked highest and second highest, respectively. However, the relative importance of the other two attributes varied by preferred therapy: treatment regimen was ranked higher by participants who preferred as-needed treatment than by participants who preferred maintenance treatment. CONCLUSIONS: Knowledge of patient preferences for treatment attributes together with regimen characteristics can be used in shared decision-making regarding choice of treatment for patients with mild-moderate asthma. TRIAL REGISTRATION NUMBER: ACTRN12616000377437.

Novel Cyclic Lipopeptide Antibiotics: Effects of Acyl Chain Length and Position.

Multidrug-resistant bacteria are a global health problem. One of the last-resort antibiotics against Gram-negative bacteria is the cyclic lipopeptide colistin, displaying a flexible linker with a fatty acid moiety. The aim of the present project was to investigate the effect on antimicrobial activity of introducing fatty acid moieties of different lengths and in different positions in a cyclic peptide, S3(B), containing a flexible linker. The lipidated analogues of S3(B) were synthesized by 9-fluorenylmethoxycarbonyl (Fmoc) solid-phase peptide synthesis. Following assembly of the linear peptide by Fmoc solid-phase peptide synthesis, on-resin head-to-tail cyclization and fatty acid acylation were performed. The antimicrobial activity was determined against the ESKAPE pathogens, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Escherichia coli. Furthermore, hemolytic activity was determined against human erythrocytes. A total of 18 cyclic lipopeptides were synthesized and characterized. It was found that introduction of fatty acids in positions next to the flexible linker was more strongly linked to antimicrobial activity. The fatty acid length altered the overall hydrophobicity, which was the driving force for both high antimicrobial and hemolytic activity. Peptides became highly hemolytic when carbon-chain length exceeded 10 (i.e., C10), overlapping with the optimum for antimicrobial activity (i.e., C8-C12). The most promising candidate (C8)5 showed antimicrobial activity corresponding to that of S3(B), but with an improved hemolytic profile. Finally, (C8)5 was further investigated in a time-kill experiment.

Fluorescent Analogues of Human α-Calcitonin Gene-Related Peptide with Potent Vasodilator Activity.

: Human α-calcitonin gene-related peptide (h-α-CGRP) is a highly potent vasodilator peptide that belongs to the family of calcitonin peptides. There are two forms of CGRP receptors in humans and rodents: α-CGRP receptor predominately found in the cardiovascular system and ß-CGRP receptor predominating in the gastrointestinal tract. The CGRP receptors are primarily localized to C and Aδ sensory fibers, where they are involved in nociceptive transmission and migraine pathophysiology. These fibers are found both peripherally and centrally, with extensive perivascular location. The CGRP receptors belong to the class B G-protein-coupled receptors, and they are primarily associated to signaling via Gα proteins. The objectives of the present work were: (i) synthesis of three single-labelled fluorescent analogues of h-α-CGRP by 9-fluorenylmethyloxycarbonyl (Fmoc)-based solid-phase peptide synthesis, and (ii) testing of their biological activity in isolated human, mouse, and rat arteries by using a small-vessel myograph setup. The three analogues were labelled with 5(6)-carboxyfluorescein via the spacer 6-aminohexanoic acid at the chain of Lys24 or Lys35. Circular dichroism (CD) experiments were performed to obtain information on the secondary structure of these fluorescently labelled peptides. The CD spectra indicated that the folding of all three analogues was similar to that of native α-CGRP. The three fluorescent analogues of α-CGRP were successfully prepared with a purity of >95%. In comparison to α-CGRP, the three analogues exhibited similar efficacy, but different potency in producing a vasodilator effect. The analogue labelled at the N-terminus proved to be the most readily synthesized, but it was found to possess the lowest vasodilator potency. The analogues labelled at Lys35 or Lys24 exhibited an acceptable reduction in potency (i.e., 3-5 times and 5-10 times less potent, respectively), and thus they have potential for use in further investigations of receptor internalization and neuronal reuptake.

The accuracy of clinician evaluation of interproximal contacts using different methods.

STATEMENT OF PROBLEM: Complete seating of a single crown may not be possible if the interproximal contacts are excessively tight. Incomplete seating can lead to open margins, inflammation of the gingival tissue, and recurrent dental caries. PURPOSE: The purpose of this in vitro study was to determine the accuracy of 3 different methods of evaluating interproximal contacts when seating a single crown. MATERIAL AND METHODS: Thirty-five restorative dentists practicing in the Lincoln, Nebraska, area were polled to determine the methods they used most commonly to evaluate the interproximal contacts of crowns. These dentists then evaluated the interproximal contacts of 9 anatomic contour zirconia crowns on a dentoform using 3 different methods: floss and explorer, occlusal articulating film (AccuFilm), and shim stock. Crown fit was evaluated using 1 method at a time. Each crown was recorded as either "accept" or "reject" according to the individual clinician. All data were analyzed with the McNemar test (α=.05). RESULTS: Of the 35 restorative dentists polled, 34 identified floss and explorer, 9 identified occlusal articulating film, 3 identified shim stock, and 3 identified an occlusal spray as their method of evaluating interproximal contacts. These methods were used either alone or in conjunction with other methods. Evaluation of the in vitro data revealed that shim stock and occlusal articulating film were significantly more accurate than floss and explorer for assessing interproximal contacts in poorly fitting crowns (P<.001). For well-fitting crowns, shim stock and occlusal articulating film were significantly more accurate than floss and explorer (P<.001). CONCLUSIONS: This study showed that the floss and explorer method was the least accurate means of evaluating the interproximal fit of crowns. Shim stock provided the most accurate method of evaluating interproximal contact, and occlusal articulating film provided both high accuracy and a visible mark to facilitate adjustment.

Structure Elucidation of Prenyl- and Geranyl-Substituted Coumarins in Gerbera piloselloides by NMR Spectroscopy, Electronic Circular Dichroism Calculations, and Single Crystal X-ray Crystallography.

Crude ethyl acetate extract of Gerbera piloselloides (L.) Cass. was investigated by dual high-resolution PTP1B/α-glucosidase inhibition profiling and LC-PDA-HRMS. This indicated the presence of a series of unprecedented prenyl- and geranyl-substituted coumarin derivatives correlated with both α-glucosidase and PTP1B inhibitory activity. Repeated chromatographic separation targeting these compounds led to the isolation of 13 new compounds, of which ten could be isolated as both enantiomers after chiral separation. The structures of all isolated compounds were characterized by HRMS and extensive 1D and 2D NMR analysis. The absolute configurations of the isolated compounds were determined by comparison of experimental and calculated electronic circular dichroism spectra. Compound 6 features a rare furan-oxepane 5/7 ring system, possibly formed through addition of a geranyl unit to C-3 of 5-methylcoumarin, representing a new type of geranyl-substituted coumarin skeleton. Compounds 19 and 24 are the first examples of dimeric natural products consisting of both coumarin and chromone moieties.

Pancreatic grade 3 neuroendocrine tumors behave similarly to neuroendocrine carcinomas following resection: a multi-center, international appraisal of the WHO 2010 and WHO 2017 staging schema for pancreatic neuroendocrine lesions.

BACKGROUND: In 2017, the WHO updated their 2010 classification of pancreatic neuroendocrine tumors, introducing a well-differentiated, highly proliferative grade 3 tumor, distinct from neuroendocrine carcinomas. The aim of this study was to investigate the clinical significance of this update in a large cohort of resected tumors. METHODS: Using a multicenter, international dataset of patients with pancreatic neuroendocrine lesions, patients were classified both according to the WHO 2010 and 2017 schema. Multivariable survival analyses were performed, and the models were evaluated for discrimination ability and goodness of fit. RESULTS: Excluding patients with a known germline MEN1 mutation and incomplete data, 544 patients were analyzed. The performance of the WHO 2010 and 2017 models was similar, however surgically resected grade 3 tumors behaved very similarly to neuroendocrine carcinomas. CONCLUSION: The addition of a grade 3 NET classification may be of limited utility in surgically resected patients, as these lesions have similar postoperative survival compared to carcinomas. While the addition may allow for a more granular evaluation of novel treatment strategies, surgical intervention for high grade tumors should be considered judiciously.

Preoperative imaging characteristics predict poor survival and inadequate resection for left-sided pancreatic adenocarcinoma: a multi-institutional analysis.

BACKGROUND: Optimal treatment of pancreatic ductal adenocarcinoma of the neck, body and tail (PDAC-NBT) necessitates R0 surgical resection. Preoperative radiographic identification of patients likely to achieve successful oncologic resection remains difficult. This study seeks to identify preoperative imaging characteristics predictive of non-R0 resections or impaired survival for PDAC-NBT. METHODS: Patients at five high-volume centers who underwent resection for PDAC-NBT were retrospectively analyzed. The most immediate preoperative cross-sectional scan was assessed along with outcome measures of overall survival and margin status. RESULTS: 330 patients were treated between 2001 and 2016. Margin status included 247 R0 (78.2%), 67 R1 (21.2%), and 2 R2 (0.6%). A non-R0 resection predicted worse survival (p = 0.0002). On preoperative imaging, patients with tumors greater than 20 mm, tumor attenuation greater than 70 Hounsfield units, or who demonstrated pancreatic atrophy and/or calcifications also had worse survival (p = 0.010, p = 0.036, p = 0.025 respectively). Patients with tumors interfacing with the splenic artery or vein or extending posteriorly achieved fewer R0 resections (p = 0.0006, p = 0.0004, p = 0.001, respectively). CONCLUSION: Preoperative cross-sectional imaging can identify tumor characteristics associated with poor survival and non-R0 resection. Further investigation is needed to identify the appropriate surgical and treatment modifications necessary to clinically benefit this subset of patients.

The prototypical proton-coupled oligopeptide transporter YdgR from Escherichia coli facilitates chloramphenicol uptake into bacterial cells.

Chloramphenicol (Cam) is a broad-spectrum antibiotic used to combat bacterial infections in humans and animals. Cam export from bacterial cells is one of the mechanisms by which pathogens resist Cam's antibacterial effects, and several different proteins are known to facilitate this process. However, to date no report exists on any specific transport protein that facilitates Cam uptake. The proton-coupled oligopeptide transporter (POT) YdgR from Escherichia coli is a prototypical member of the POT family, functioning in proton-coupled uptake of di- and tripeptides. By following bacterial growth and conducting LC-MS-based assays we show here that YdgR facilitates Cam uptake. Some YdgR variants displaying reduced peptide uptake also exhibited reduced Cam uptake, indicating that peptides and Cam bind YdgR at similar regions. Homology modeling of YdgR, Cam docking, and mutational studies suggested a binding mode that resembles that of Cam binding to the multidrug resistance transporter MdfA. To our knowledge, this is the first report of Cam uptake into bacterial cells mediated by a specific transporter protein. Our findings suggest a specific bacterial transporter for drug uptake that might be targeted to promote greater antibiotic influx to increase cytoplasmic antibiotic concentration for enhanced cytotoxicity.